I have washed Pendleton wool (the men's shirt weight).
It turned out well. I can't tell the washed from the unwashed.
I bought five yard lengths of burgundy, navy, and hunter green way back when the stores were called Minnesota Fabrics. I wonder why I did not buy any black. I think I was going to make myself suits or something. Maybe the store did not have a long piece of black in stock.
I have washed DH's Pendleton shirts at home. I soak them in cool/warm water, rinse in the same temperature water - spin dry or towel dry. No wringing by hand. I might partially dry them in the dryer and then let them air dry on a hanger. They turned out well.
I think they got by cleaner by washing than taking them to a dry cleaner.